Abstract

Understanding drug-protein interactions and downstream effects of these interactionsunderpins much of clinical pharmacology. By studying the protein targets of a smallmolecule we can learn about the action of this compound in the body, and thisinformation can lead to greater understanding of mechanisms and clinical effects.We probed the polypeptide interactions of five small molecules using a humanvascular phage display library, with the intention to elucidate previously unknownprotein targets for the small molecule in human vasculature. A method for studyingthe chemical nature of this interaction was also developed.The photochemical immobilisation system used - Magic Tag® - was developed as ameans of immobilising small molecules without concealing any facet of themolecule from the interaction study. Five different photochemistries are displayed ina multi-well format, to maximise diversity in the display of the small molecule. Ahuman vascular tissue T7Select® bacteriophage display library was prepared frominternal mammary artery tissues donated from patients undergoing coronary arterybypass surgery. Biopanning of the immobilised small molecule against this libraryallowed hypothesis generating analysis of small molecule-polypeptide interactions.Because of the non-selective nature of the photochemical immobilisation of thesmall molecule, several regioisomers might be expected to form on the Magic Tag®surface. To be able to connect a protein interaction with a specific face of the smallmolecule, analysis of this regio-non-specific interaction must be undertaken. For thispurpose a cleavable resin analogue of the Magic Tag® surface was prepared.